Roller gates are typically used for Gravity/Emergency closure and where waterways are too large to efficiently use slide gates.
The rollers (wheels) are mounted on shafts fixed laterally to the leaf on vertical girders have double functions: reduce the friction forces and transfer the water load to the embedded parts.
Upstream sealing is preferred to reduce downpull loads, allow good venting through the roller gate upstream gap and to facilitate access to penstocks and tunnels.
Downstream sealing uses the water loads to compress the joints and enhance sealing.
